As a child he enjoyed hurting animals and tortured guinea pigs and frogs - skinning the latter before breaking their legs. He kept two pet snakes at Tracey Connelly's home and fed them dead chicks, mice and rabbits.

His fascination with causing pain to animals saw him prosecuted for that very obsession by the RSPCA.

Barker, who had a child with another woman before he met Connelly through his work as a handyman, had no previous convictions before Peter's death.

However, he was known to police after being arrested in the mid 1990s on suspicion of torturing his dying grandmother to get her to change her will.

Both he and Owen were initially charged with assaulting Hilda Barker, 82, at her home in Whitstable, Kent in 1995.

She told police the pair had locked her in a wardrobe to force her change her will in their favour and allegedly beat her until she was badly bruised.

They also were said to have dressed up in Guy Fawkes masks to scare her.

Mrs Barker was so shaken by her experience that she was moved to a care home where she died from pneumonia in January 1996.

Barker and Owen were arrested and charged but the case was dropped after the frail woman's death due to a lack of admissible evidence.

Mrs Barker's neighbour Jacqueline Cole, 58, said: "We used to see them when they came down from London. They were teenage lads.

"They used to come down with their parents until the very last time, when she had problems. Every time they came she was bruised. She was frightened every time they came down."

Although he had no convictions before the trial into Peter's death, he was found guilty of raping a two-year-old girl in May this year.

His older brother Owen, nicknamed "Fat Boy" as a child, had previous convictions for theft and arson after he set his own home on fire to try win compensation.

Born in February 1972, he was previously married with four children before he arrived at Barker and Connelly's house accompanied by his 15-year-old runaway girlfriend.

It was then that Peter's injuries escalated and it is understood he changed his name to Owen after the child's death.

Owen put pressure on the teenager to implicate Barker during last year's trial and she was later discredited as a witness.

At the Old Bailey trial, both Owen and Barker tried to blame each other for Peter's death, claiming each had a history of violence and implying each had hurt their sister Susan when they were children.

The 36-year-old told the court she had seen the brothers together in a flat in London: "Steven came to the window. He looked scared. Jason was behind him.

"A few days later, Steven had cigarette burns on his hands. He was petrified of Jason."

Giving evidence, Barker, who was treated for alcoholism in 2000, tried to portray himself as the victim: "There are lots of things that I could tell you about Jason and what he's done in the past and what he's like, but I'm scared to because I really believe he will try to have me killed."